List of top Physics Questions

An L-C-R circuit contains \( R = 50 \, \Omega \), \( L = 1 \, \text{mH} \), and \( C = 0.1 \, \mu\text{F} \). The impedance of the circuit will be minimum for a frequency of?

A circular current carrying coil has a radius \( R \). The distance from the center of the coil on the axis, where the magnetic induction will be \( \frac{1}{8} \) to its value at the center of the coil is?

The incorrect statement regarding the lines of force of the magnetic field \( B \) is?

An eye can detect \( 5 \times 10^4 \) photons per square meter per second of green light ( \( \lambda = 500 \, \text{nm} \)) while the ear can detect \( 10^{-12} \, \text{W/m}^2 \). The factor by which the eye is more sensitive as a power detector than ear is close to?

During charging a capacitor, variations of potential \( V \) of the capacitor with time \( t \) is shown as?

When a resistor of 11 Ω is connected in series with an electric cell, the current following in it is 0.5 A. Instead, when a resistor of 5Ω is connected to the same electric cell in series, the current increases by 0.4 A. The internal resistance of the cell is?

A battery is charged at a potential of 15 V in 8 h when the current flowing is 10 A. The battery on discharge supplies a current of 5 A for 15 h. The mean terminal voltage during discharge is 14V. The watt-hour efficiency of the battery is?

Following process is known as?

If the electron in the hydrogen atom jumps from the third orbit to second orbit, the wavelength of the emitted radiation in terms of Rydberg constant is?

Silver has a work function of 4.7 eV. When ultraviolet light of wavelength 100 nm is incident on it, a potential of 7.7 V is required to stop the photoelectrons from reaching the collector plate. How much potential will be required to stop photoelectrons when light of wavelength 200 nm is incident on it?

If the distance of 100 W lamp is increased from a photocell, the saturation current in the photocell varies with the distance \( d \) as?

In hydrogen discharge tube, it is observed that through a given cross-section \( 3.31 \times 10^{15} \) electrons are moving from right to left and \( 3.12 \times 10^{8} \) protons are moving from left to right. The current in the discharge tube and its direction will be?

A Zener diode, having breakdown voltage equal to 15 V, is used in a voltage regulator circuit shown in figure. The current through the diode is?

In a semiconductor, separation between conduction and valence band is of the order of?

The resistance of a germanium junction diode whose \( V-I \) is shown in figure is ( \( V_k = 0.3 \, V \))?

The activity of a radioactive sample is measured as \( N_0 \) counts per minute at \( t = 0 \) and \( N \) counts per minute at \( t = 5 \) min. The time, in minutes, at which the activity reduces to half its value is?

Which has more luminous efficiency?

If 1000 droplets each of potential 1 V and radius \( r \) are mixed to form a big drop, then the potential of the drop as compared to small droplets will be?

A resistor of 6kΩ with tolerance 10% and another resistance of 4kΩ with tolerance 10% are connected in series. The tolerance of the combination is about?

An ammeter and a voltmeter of resistance \( R \) are connected in series to an electric cell of negligible internal resistance. Their readings are A and V respectively. If another resistance \( R' \) is connected in parallel with the voltmeter, then?

If we add impurity to a metal, those atoms also deflect electrons. Therefore?

The output Y of the logic circuit shown in figure is best represented as?

A neutron is moving with velocity \( v \). It collides head on and elastically with an atom of mass number \( A \). If the initial kinetic energy of the neutron is \( E \), then how much kinetic energy will be retained by the neutron after reflection?

A proton and an α-particle, accelerated through the same potential difference, enter a region of uniform magnetic field normally. If the radius of the proton orbit is 10 cm, then the radius of α-particles is?

If a magnet is suspended at angle 30° to the magnet meridian, the dip of needle makes angle of 45° with the horizontal, the real dip is?